The invention relates to a printhead suitable for use with image forming systems, and more particularly relates to a modular printhead arrangement.
Different printhead technologies in use today in image forming systems create and reproduce images in different ways. Some of these technologies include a process of charging a dielectric layer on a surface of a drum with an electronic image. A developer then transfers developer material, such as toner particles, to the charged surface. Rollers then press a printing medium, such as a sheet of paper, against the developed toner particles to permanently affix the toner particles to the paper sheet.
An alternative arrangement provides a photoconductive member within the imaging device charged to a substantially uniform potential. The light image of a document projects onto the photoconductive member, dissipating the charge on selected areas of the photoconductive member. The dissipation of charge results in an electrostatic image forming on the photoconductive member, which corresponds to a particular image on a document. A similar process develops a toner particle image and transfers it to a paper sheet.
One specific type of image forming system is an electrostatographic image system. Such image forming systems typically include at least one image forming device, such as a printhead. A known configuration for a printhead is a three layer structure. A first layer is an electrode layer, a second layer is a dielectric layer, and a third layer is another electrode layer. Electrodes within each of the electrode layers cross with electrodes from the other of the electrode layers, forming intersections, physically separated by the dielectric layer. These electrode intersections form charge generation sites.
Current printhead technology has resulted in a combination of layers, in addition to the basic three layers, to form the printhead. Some of the added layers are relatively expensive, causing the cost for the overall printhead to exceed that which is supported by the marketplace.
There exists in the art a need for a modular printhead having the ability to separate a first collection of predetermined layers relatively permanently affixed to a print engine from a second collection of predetermined layers residing in a relatively disposable component thereof.
A modular printhead, according to one aspect, includes a first printhead component having at least a first electrode, a second electrode. A second component of the printhead can have a third electrode. The first printhead component of the printhead is separable from the second component and couples thereto in a removable and replaceable manner. A fastening mechanism or mounting element can press the components together, holding them in position.
The first electrode is an RF-line, or drive, electrode or electrode array, the second electrode is a finger electrode or electrode array, and the third electrode is a screen electrode or electrode array, in more common configurations and according to the teachings of the present invention. The first printhead component further includes a dielectric layer, to electrically insulate the first electrode (RF-line electrode) from the second electrode (finger electrode). A number of different materials can form the dielectric layer, including semi-conductor materials.
A spacer layer separates the second electrode and the third electrode in accordance with further aspects of the present invention. Mounting blocks mount the third electrode in place.